Packing list for the most comfy rv experience....

Be a minimalist. Your camper will be more cozy if it is NOT full of stuff cluttering it up.

Given your water disposal situation, I would do minimal cooking and eat out of disposable dishes. Take pre-cooked food that is easy to heat up--soups, spaghetti sauce etc. The person who does the cooking should be in charge of all kitchen stuff and decide what is needed.

You will not need a lot of towels if you are not there more than a few days in a row.

Start out with minimal stuff, and keep a running list.